Overlooked roles of pharmaceutical metabolic products in stimulating microbial metabolism and antibiotic resistance gene dissemination of anaerobic sludge

Despite the widespread environmental occurrence of non-antibiotic pharmaceuticals, their roles in shaping the dissemination behaviors of antibiotic resistance genes (ARGs) in wastewater treatment systems remain poorly understood. In particular, focus of the previous studies have been mainly on the original pollutants while overlooking their transformation products, possibly resulting in underestimation of their true ecological risks. Here, we unveiled more profound impacts of the biotransformation product of metformin (MET, a non-antibiotic pharmaceutical) than itself on the microbial community structure and ARG propagation of wastewater anaerobic sludge.